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cal·lous

(kăləs)

adj.

1. Having calluses; toughened: callous skin on the elbow.

2. Emotionally hardened; unfeeling: a callous indifference to the suffering of others.

tr. & intr.v. cal·loused, cal·lous·ing, cal·lous·es

To make or become callous.

[Middle English, from Old French cailleux, from Latin callōsus, from callum, hard skin.]

callous·ly adv.

callous·ness n.

Usage Note: Do not confuse the adjective callous, as in Years of dealing with criminals had left her callous, with the noun callus, as in I have a callus on my thumb. Also, do not confuse the verb callous, which means "to make or become callous," with the verb callus "to form or develop hardened tissue."

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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